[Logstash] LoadError: no such file to load — i18n

In CentOS 5.5, I want to install the logstash agent to forward logs.
Because it was older system and no one would upgrade it, the original java version is 1.6.
I always got the error about “LoadError: no such file to load — i18n” when I started the logstash service.
After upgrading the java version, it’s work.
So the minimum requirements for java version is 1.7, I got….